BOSTON — When Boston Celtics coach Doc Rivers gave his starters a breather to start the fourth quarter in Game 4 of the NBA finals, he told them not to get too comfortable.

"Doc was like, 'One minute, and I'm putting you in the game. You're not sitting too long, so just be ready,"' Celtics captain Paul Pierce said. "Then you look up: We tie the game, then go up two, three and then they push the lead to seven. ... It was beautiful to watch, just being a cheerleader on the sideline."

Glen "Big Baby" Davis led the Celtics bench on a game-changing run Thursday night, scoring half of his 18 points in the fourth quarter as Boston pulled away from the Los Angeles Lakers to win 96-89 and knot the best-of-seven series at two games apiece.

Game 5 is Sunday night in Boston.

"We know what to do. We know how to play. We know how to get it done," said Lakers forward Pau Gasol, who scored 21 points to go with a game-high 33 for Kobe Bryant. "And we know how important Game 5 will be, so we've just got to get ourselves mentally and physically ready ... to accomplish our mission."

Pierce scored 19 points, Kevin Garnett had 13 and Ray Allen bounced back from a seven-quarter shooting slump to score 12 points for Boston. But the new Big Three that led the Celtics to their unprecedented 17th NBA title in 2008 — beating the Lakers in the finals — was on the bench for much of the fourth-quarter run that gave Boston the lead for good.

And that was fine with them.

"I don't think guys really care and that's why we're here, it really is," Rivers said. "(Rajon) Rondo and the rest of them, they were begging me to keep guys in. 'Don't take them out! Don't take them out!' It was great. That's the loudest I've seen our bench, and it was the starters cheering from the bench."